ROBERT SIEGEL, HOST:
Fighting dust storms is expensive. The government spends billions of dollars trying to reduce this kind of environmental damage. And environmentalists say that money, at least the way it's spent now, doesn't buy change that lasts.
NPR's Dan Charles has the story.
DAN CHARLES, BYLINE: Neil Shook was relaxing at home in Woodworth, N.D., on a Saturday afternoon just over a week ago.
NEIL SHOOK: And my wife was outside, and she yelled at me to come outside and take a look at this.
CHARLES: A massive brown cloud covered the horizon to the west. It was a dust storm. Although Shook, who's a scientist with the U.S. Fish and Wildlife Service, does not like to call it dust.
SHOOK: I like to refer to it as soil because that's basically what it is. You know, we saw this huge soil cloud moving from west to east across the landscape.
CHARLES: Shook makes a point of calling it soil to remind people that this is a vital natural resource essential for growing food. And it's been blowing away ever since farmers first plowed up the prairie, gradually or catastrophically, in the case of the dustbowl in the 1930s. And Shook says the problem is getting worse again, driven by more frequent droughts but also because farmers again have taken land where grass used to grow and plowed it up, exposing vulnerable soil.
SHOOK: The first soil storm that I saw was in 2013. And that was about the height of all of the grassland conversion that was happening in this area.
CHARLES: And this is where government policy comes in. The Department of Agriculture rents land from farmers and pays them to grow grass or trees or wild flowers to protect the soil and also provide habitat for wildlife. It's called the Conservation Reserve Program or CRP. And 10 years ago, across the country, there was more land in the CRP than in the entire state of New York.
In North Dakota, it was huge. CRP land covered 5,000 square miles. Then farming got more profitable, and farmers let those contracts expire. They plowed and planted more valuable crops like corn and soybeans. The amount of CRP land in North Dakota fell by more than half. And according to environmentalist Craig Cox, this means billions of dollars that the government spent protecting that land was basically wasted.
CRAIG COX: We're not making lasting change. The benefit is lost really quickly.
CHARLES: Cox is an expert on farming at the Environmental Working Group, which just released a report calling for the government to stop protecting land just for 10 years at a time. Instead, he says the government should expand programs that paid landowners for long-term easements, protecting land from plowing for the next 30 years or forever.
COX: That's where you really start to make environmental gains.
CHARLES: Buying up rights to plant crops is expensive, though. So the government would have to spend its money just in the places where it can do the most good, places, for instance, where that money will keep the most soil from blowing away. Dan Charles, NPR News.
(SOUNDBITE OF MEDESKI SCOFIELD MARTIN AND WOOD'S "IN CASE THE WORLD CHANGES ITS MIND")